In various fields including manufacturing a semiconductor device such as LSI, forming a liquid crystal display face such as LCD panels, and manufacturing circuit substrates for a thermal head and so on, a formation of resist patterns on substrates is conducted for a formation of fine elements or for fine processing. Formation of these resist patterns employs a so-called photolithographic method which involves a light exposure of a photosensitive resin composition by a selective irradiation with actinic rays such as ultraviolet rays, deep ultraviolet rays, an excimer laser, X-rays or electron beams and a subsequent development treatment thereof. In this photolithographic method, a positive- or negative-working photosensitive resin composition is used to form resist patterns.
As semiconductor devices and so on have been highly integrated in recent years, a line width of a wire and a gap between separated wires required in these manufacturing processes come to be further finer, and in coping therewith, light-exposure devices utilizing a short-wavelength light source such as g-line, i-line, an excimer laser and so on are used, and a phase-shift mask and so on are also used in light exposure. In the conventional photolithographic technology using light exposure, however, a formation of fine resist patterns exceeding the limit of wavelength is difficult and the light-exposure devices for short wavelength and the devices using a phase-shift mask are expensive. Accordingly, methods wherein resist patterns are formed from a known positive- or negative-working photosensitive resin composition by a known pattern-forming device without using the expensive devices and the formed resist patterns are effectively made fine have been extensively studied. As one method of making resist patterns fine effectively, there is proposed a method of forming fine resist patterns below the limit of resolution effectively as follows. That is, patterns are formed from a known photosensitive resin composition such as a chemically amplified photoresist by a conventional method, a coated layer comprising a fine pattern forming material containing a water-soluble resin is applied onto the formed resist patterns, the resist is heated and/or exposed to light to permit an acid formed in the resist or an acid present in the resist diffusing into the coated layer, and by this diffused acid, the coated layer in the vicinity of the resist is crosslinked and cured. Thereafter the non-crosslinked coated layer is removed to thicken the resist patterns. As a result, the width of a gap between a resist pattern and a resist pattern is decreased, the resist patterns are made fine by reducing the separation size of the resist patterns or the size of a hole opening, and the fine resist patterns with the limit of resolution or less are effectively formed (see, for example, JP 5-241348 A, JP 6-250379 A, JP 10-73927 A, and JP 11-204399 A).
At present, upon effectively forming a fine resist pattern having a size of a resolution limit or less after a coated layer is formed by applying a fine pattern forming material on a resist pattern, a heating and/or an exposure to light treatment is carried out and a development is made, in order to remove the above uncrosslinked layer a developer for exclusive use (see JP2002-49161A, for example) or a developer comprising a mixed solution of water and a water-soluble organic solvent is being applied. This is because of incomplete removal of uncrosslinked area of the coated layer by a development only with water due to poor solubility of a fine pattern forming material so far known in water, generating a residue of dissolution to cause a lot of development defects. Because of this, a fine pattern formation by a development only by water is difficult from the view point of development defects at present.
Problems to be Solved by the Invention
Accordingly an objective of the present invention is to offer a fine pattern forming material, wherein the problems in the past are improved, that is a solubility in water of an uncrosslinked coated layer is raised, a development only by water can be carried out, less development defects are brought by the development only by water and no practical problems are caused.
And other objective of the present invention is to offer a fine pattern forming method, whereby a resist pattern can be formed, wherein less development defects are brought by a development only by water and no practical problems are caused in the method wherein a coated layer is formed on a resist pattern by applying the fine pattern forming material on the resist pattern, a crosslinked layer is formed in the vicinity of the resist pattern by diffusing an acid generated by heating, etc. into the coated layer to form a crosslinked layer in the vicinity of the resist pattern and an uncrosslinked layer is removed by a development.
Measures to Solve the Problems
As a result of eager studies and examinations, the present inventors found that in the fine pattern forming material comprising a water-soluble resin, a water-soluble crosslinking agent and water or mixed solvent of water and a water-soluble organic solvent, the fine pattern forming material comes to be developable by water by incorporating an amine compound into the fine pattern forming material and then the above theme can be solved, the theme can be more accurately solved by applying particular materials as a water-soluble resin, a water-soluble crosslinking agent and an amine compound, and further the above theme can be solved more accurately by selection of the amine compound and a coatability of the fine pattern forming material can be raised by incorporating a surfactant to reach to the present invention.
It means that the present invention relates to the fine pattern forming material which is characterized in comprising a water-soluble resin, a water-soluble crosslinking agent and water or a mixed solvent of water and a water-soluble organic solvent and that the above-described fine pattern forming material comprises an amine compound which is at least one selected from the group consisting of a primary amine compound consisting of hydrazine, urea, amino acid, a glucosamine derivative, a polyallylamine derivative, an amino group of which is at least one selected from the group consisting of an alkyloxycarbonyl group, an aryloxycarbonyl group and an alkylcarbonyl group and is partially protected in the above fine pattern forming material, and a quaternary amine compound thereof consisting of dimethyl ammonium salt, trimethyl ammonium salt, tetramethyl ammonium salt, dimethyl ethyl benzyl ammonium salt or N-methylpyridinium salt of the above primary amine compounds and that pH value of the above fine pattern forming material exceeds 7.0.
And also the present invention relates to a fine pattern forming material, wherein the water-soluble resin is at least one selected from the group consisting of a polyvinylalcohol derivative, a polyvinylpyrrolidone derivative and a polyacrylic acid derivative, the water-soluble crosslinking agent is at least one selected from the group consisting of a melamine derivative and a urea derivative.
Further the present invention relates to the fine pattern forming material, wherein the amine compound described before is a polyallylamine derivative and the molecular weight thereof is 1,000 to 10,000 in any one of the above fine pattern forming materials.
And also the present invention relates to a fine pattern forming material, further containing a surfactant in any one of the above fine pattern forming material.
And also the present invention relates to a fine pattern forming material, wherein the surfactant is at least one selected from the group consisting of an anionic surfactant consisting of alkylsulfonate, alkylbenzene sulfonic acid and alkylbenzenesulfonate, a cationic surfactant consisting of laurylpyridinium chloride and laurylmethylammonium chloride, a nonionic surfactant consisting of polyoxyethylene octylether, polyoxyethylene laurylether and polyoxyethylene acetylenic glycolether in the above fine pattern forming material.
And the present invention also relates to a fine pattern forming method which is characterized in comprising a resist pattern forming step comprising a photoresist on a substrate, a step wherein a coating layer is formed by applying any of the before-described fine pattern forming material, a step wherein the area neighboring to a resist pattern is crosslinked and/or cured by heating the before-described resist pattern and the before-described coated layer and by a diffusion of an acid from the resist pattern and a step wherein the before-described coated layer is developed by water after heating.
Effects of the invention
In the present invention, a water-soluble fine pattern forming material can be obtained by incorporating an amine compound into the fine pattern forming material. By using this water-soluble fine pattern forming material, a coated layer is formed on a resist pattern generating an acid by heating, etc., the coated layer in the vicinity of the resist pattern is crosslinked or cured by heating, is developed and the number of development defects are also reduced by water development to be able to form a pattern without problems in a practical use. And also by further incorporating a surfactant into the fine pattern forming material, the fine pattern forming material wherein a minimum coating amount is reduced and a pattern forming method using the same can be offered. By the fine pattern forming material of the present invention and the fine pattern forming method applying this fine pattern forming material, in a fine processing for manufacturing electronic parts such as a semiconductor, etc. or a three-dimensional fine structured article, a pattern having a size of a limit resolution of an exposure to light or less can be formed in accordance with a design rule as designed in high accuracy, high-through-put and inexpensively.